P-3.1 Apply energy formulas to determine potential and kinetic energy and explain the transformation from one to the other.
P-3.2 Apply the law of conservation of energy to the transfer of mechanical energy through work.
P-3.3 Explain, both conceptually and quantitatively, how energy can transfer from one system to another (including work, power, and efficiency).
P-3.4 Explain, both conceptually and quantitatively, the factors that influence periodic motion.
P-3.5 Explain the factors involved in producing a change in momentum (including impulse and the law of conservation of momentum in both linear and rotary systems).
P-3.6 Compare elastic and inelastic collisions in terms of conservation laws.

Practice
Test

Study
Guide

Objectives

Essential Question: What is energy?

Linear and Rotational Kinetic Energy

State that kinetic energy cannot be negative.

Solve problems in which work = change in kinetic energy.

Demonstrate that while momentum is conserved, kinetic energy is not conserved in an inelastic collision.

State the mathematical definition of rotational kinetic energy.

K = 1/2 I w2

State that the total kinetic energy of an object is the sum of rotational and linear kinetic energies, because energy is a scalar. Note: rotational and linear momentum cannot be added together.

Demonstrate that while momentum is conserved, kinetic energy is not conserved in a spinning ice skater problem.

Determine if both momentum and kinetic energy are conserved in elastic collisions of 2 carts on a track.

Background

Physics has 2 simplified methods of modelling collisions that can be used to analyze real world conditions: elastic and inelastic models. Both contain the simplifying assumption that fricition forces are negligible. Momentum is conserved in both cases and kinetic energy is conserved for elastic models.

Hypothesis

If a video analysis of the collision indicates a negligible loss of kinetic energy and momentum in the collision then it can be reasonably modeled as elastic.

Data,
Calculations

Using Logger Pro software, perform video analysis on the elastic collision video with equal mass in the Advanced Physic --Mechanics folder. Make a table and report velocities, kinetic energies, and momentums for the carts both before and after the collisions, calculate the % momentum and % kinetic energy lost during the collision.

Conclusions

Answer the research question, discuss sources of error and possible improvements.

Determine if both momentum and kinetic energy are conserved in an inelastic collision of 2 carts on a track.

Background

Physics has 2 simplified methods of modelling collisions that can be used to analyze real world conditions: elastic and inelastic models. Both contain the simplifying assumption that fricition forces are negligible. Momentum is conserved in both cases and kinetic energy is conserved for elastic models.

Hypothesis

If a video analysis of the collision indicates a negligible loss of momentum in the collision then it can be reasonably modeled as obeying conservation of.

Data,
Calculations

Using Logger Pro software, perform video analysis on both the elastic collision videos in the Advanced Physics--Mechanics folder. Make a table and report velocities, kinetic energies, and momentums for the carts both before and after the collisions, calculate the % momentum and % kinetic energy lost during the collision. (Note: kinetic energy loss should be high in an inelastic collision.)

The left cart mass = 1.043 kg, the right cart mass = 0.514 kg

Conclusions

Answer the research question, discuss sources of error and possible improvements.

Calculate gravitational potential energy (flat Earth model). Ug = mgh, Note that an arbitrary reference point must be selected as having zero gravitational potential energy. Depending on the reference selected, U can be negative.

State a condition that should be satisfied when modeling a system as though it has a constant level of mechanical energy.

No energy is lost as heat

Write an energy balance equation for systems that can be modelled as having constant mechanical energy (conservation of mechanical energy).

ME = K + U

Kbefore + Ubefore = Kafter + Uafter

Solve problem in which mechanical energy is considered to be constant.

pendulums

frictionless slopes

free fall (no air resistance)

Homefun (formative/summative assessment) problems 5, 6,7 p. 291.

Essential Question:How have springs affected history in critical ways?

Spring or Elastic Potential Energy

Relevance:The practical understanding of spring potential energy has been a significant factor in shaping history with technologies such as bows and arrows, catapults, modern fire arms, clocks, vehicles, etc.

Calculate potential energy for a spring.

Us = 1/2 kx2

k= F/x , k is called a spring constant and is a measure of spring stiffness

Metacognition Problem Solving Question: Can I still work the problems done in class, several hours
or days later?
Some amount of repetition on the exact same problems is necessary to lock in
learning. It is often better to thoroughly understand a single example of a
problem type than to work example after example understanding none of them
completely.

Relevance: Good test preparation is
essential to performance in physics class.

Homefun (formative/summative assessment): turn in on the day stapled to the back of the test.

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